Splitboard bindings

ABSTRACT

Improved boot bindings for backcountry splitboarding are disclosed. Each of a pair of soft-boot bindings has an integral boot binding lower that conjoins the two halves of a splitboard without the additional weight or height of an adaptor mounting plate and extra fasteners. Attached to the integral boot binding lower are the elements of a boot binding upper. The integral boot binding lower, in combination with upper boot bindings, provides improved torsional stiffness for splitboard riding. The integral boot binding lower further includes a toe pivot for free heel ski touring. The boot bindings can be readily detached from the ski touring position and reattached to the snowboard riding position, or vice versa, as is advantageous in backcountry touring and riding.

RELATED APPLICATIONS

The present application claims the benefit of priority to U.S. PatentApplication No. 60/783,327 filed on Mar. 17, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to splitboards in Class 280/600 et seq.More particularly, the invention relates to a boot binding system thathas improved torsional stiffness for use with splitboards and that gainsits stiffness from an integral sandwich box girder construction whichgrippingly attaches to the snowboard mounting block assemblies.

2. Background of the Invention

Backcountry snowboarding appeals to riders who wish to ride untrackedsnow, avoid the crowds of commercial resorts, and spurn limitations onwhat and where they can ride. There are no ski-lifts in the backcountry,so the snowboarder must climb the slopes by physical effort. Somesnowboarders simply carry their board and hike up, but progress can bealmost impossible if the hiker sinks deep in soft snow. Travelefficiency can be improved with snowshoes, but the rider must still finda way to carry their board up the slope.

Saving effort is the name of the game in the backcountry; it determineshow many runs a rider is going to make in a day. If a rider is exhaustedby the time they reach the top of the run, they aren't going tosnowboard to the best of their ability, or enjoy themselves as much asthey could.

Splitboards are a recent improvement. When assembled, a splitboard lookslike a snowboard, but can be taken apart to form a pair of skis. Theright and left skis of a splitboard are asymmetrical; they are themirror halves of a snowboard-longitudinally cut (or “split”), andtypically have the sidecut (ie. nonlinear longitudinal edges) and camberof snowboards.

When touring cross-country and uphill to reach the slopes, the skis areworn separately. Cross-country travel on skis requires less effort thanhiking or snowshoeing. Since the rider is wearing the skis instead ofcarrying a snowboard, the effort is less tiring—the rider can glidealong, and there is no extra weight to carry up the slope. The widertrack of the splitboard skis reduces sinking in soft powder snow.

“Free heel” ski bindings and adaptors, such as telemark, randonee orAlpine Trekkers, make ski touring easier. In addition, the skis may beadapted for climbing by applying climbing skins to the lower surface ofthe skis. The use of climbing bars propped under the boot heels aids inclimbing steeper slopes and crampons may be used in icy conditions todecrease the risk of slipping. Free heel bindings, climbing skins,climbing bars and crampons are used by touring splitboarders as well.

In the occasional descent in ski touring mode, the heels of the bootbindings are either “locked down” to the skis, with descent usingconventional alpine techniques, or more commonly left free with the toeattached by a pivot, with descent using telemark ski techniques.

The splitboard reveals its true utility on the downhill rides. The riderfirst joins the two skis of the split board pair to form asnowboard-like combination. The rider's stance in the snowboard ridingconfiguration is sideways on the board, with legs spread for balance.Ideally, the rider descends the slope as if riding a snowboard, withheels and toes locked in place.

Some boards, known as “swallowtails”, are designed specially for powdersnow. These boards have forked tails that allow the tail of the board tocarve more deeply in the snow while keeping the nose of the board high.

Another version of splitboards, recently innovated in Europe, is formedwith two narrow skis and a third fitted plank between the skis. When skitouring, the extra plank must be carried. It remains to be seen whetherthis will catch on in backcountry snowboarding elsewhere.

It should be noted that downhill skiing and snowboard riding requirevery different styles and skills. With skis, the body points in the samedirection as the skis, and the skier uses hips and knees to changedirection. Knee injuries are common because the legs move separately. Ona snowboard, the body is essentially crossways on the board, and bothheels are firmly attached to the board so that the feet, ankles, hips,and upper body can be used to set the board on an edge and make a turn.Knees are more protected because both legs are firmly secured to theboard.

Backcountry splitboarding, which combines ski touring and snowboarding,thus requires boot bindings adaptable for both ski configuration (ie.one to a ski) and for snowboard configuration, (ie. joining the skis asa snowboard).

In one widely used configuration of the prior art, snowboard mountingblock elements (also termed toe and heel “pucks”) are attached in pairsto the opposing ski member halves of the splitboard. Changing theposition of the mounting blocks allows the rider to mount their bindingsat the desired angles and positions along the length of the splitboard.These mounting blocks, disclosed in U.S. Pat. No. 5,984,324 to Wariakoisand hereby incorporated in full by reference, are designed so that anadaptor mounting plate (see the C-channel, Item 74 of FIG. 6 of U.S.Pat. No. 5,984,324, also termed “slider plate”) attached to the bootmounting assembly can be slid over the toe and heel snowboard mountingblocks, conjoining the ski members of the pair. The adaptor mountingplate adds about 7 oz (or 200 g) of weight to each boot. A rear stop tabon the adaptor mounting plate prevents the boots from sliding forwardover the heel mounting block and a clevis pin is used to lock the toe ofthe adaptor mounting plate on the toe mounting blocks.

This same clevis pin is used as a pivot pin when the adaptor mountingplate is relocated to a ski mounting bracket. But experience has shownthat the forces on the pivot pin are such that the pivot pin cradle andadaptor mounting plate of the prior art rapidly fatigue and are ovallydeformed, leading to heel “fishtailing” in free heel mode, whichdestabilizes the rider and which must be repaired by replacement of theworn parts.

A second system for grippingly conjoining the ski member halves of asplitboard is disclosed in U.S. Pat. No. 6,523,851 to Maravetz, herebyincorporated in full by reference. This system employs a recessed ringwith raised flanges that mate with a clamshell adaptor plate to securethe upper boot assembly to the board. The preset angle of the footrelative to the board can be changed by use of a locking pin in therotatable lower half of the lower adaptor plate. The clamshell is hingedat the toe, but the heel can optionally be locked down. Conversion fromtouring mode to snowboard mode can be difficult with this system becausesnow often gets inside the clamshell works during touring, andconsequently this system has proved less than satisfactory in fieldexperience by snowboard riders.

Both of the above prior art splitboard systems employ the adaptormounting plates to secure the boot bindings to the board interchangeablybetween ski and snowboard configurations. In addition to the ski memberconjoining function, this approach teaches the utility of a universalmounting system for the industry-standard disk (3- or 4-hole) used inmost snowboard boot mounting systems, strap or step-in, including hard,hybrid, or soft boots. An even more complex example of an adaptor plateis shown in US 20040070176 to Miller. Examples of other mechanisms thatlack the required interchangeability include U.S. Pat. No. 5,035,443 toKinchelee, U.S. Pat. No. 5,520,406 to Anderson, and U.S. Pat. No.5,558,354 to Lion.

However, splitboarding is no longer a crossover sport. The majority ofboard riders have developed a preference for soft boots, which many findto be lighter, more comfortable, better adapted to the style of ridingthey prefer. Only a minority of riders use hard boots. Board riderstypically prefer a greater range of motion at the ankle than hard bootsprovide. Flexibility at the ankle (also known as “foot roll”) enhancesthe rider's ability to shift his or her weight and body position aroundthe board for balance and control by allowing for a range of angles thelegs can make with the board. For example in riding over a mogul, therider shifts weight to the back of the board as the angle of the slopechanges, or in carving a turn in hard snow, the rider will lean forwardon the board. Flexibility may also improve the overall ride by allowingbumps to be more readily absorbed by the ankles and knees. Thus, thefreedom of the foot to “roll”, and allow the angle of the leg to changerelative to the board, provides a performance and feel that many ridersfind desirable. Soft boots have emerged as a clear preference amongsplitboarders.

Boot bindings for use with soft boots are of two basic types: strapbindings and step-in bindings. A strap binding, which has been thetraditional type of binding for a soft boot, includes one or more strapsthat are tightened across various portions of the boot, securing theboot in a boot pocket formed by the binding upper. For example, an anklestrap may be provided to hold down a rider's heel in the heel cup and atoe strap may be provided to hold the front portion of the rider's foot.

Step-in snowboard bindings, both toe-and-heel and sole side-grip, havealso been developed for use with soft snowboard boots. Most of theserequire specially fabricated boots matched to the bindings. Newerinnovations include highback click locking mechanisms.

However, while innovation continues, the prior art has not produced aboot binding optimized for splitboarding. Multiple components of theprior art—for example, 4-hole disk bindings, adaptor mounting plates,rubber gaskets, and filled-nylon base plates-serve only to add weightand to put more height between the rider's heel and the board itself.Damaging metal fatigue of critical parts results from the design of theadaptor mounting plate and pivot pin cradle. The lack of firm broadcontact between the most commonly sold adaptor mounting plate and theboard surface also adds to the rider's instability.

Very importantly, and paradoxically, the added “flex” or “play”permitted by the engineering mechanics of the prior art adaptor mountingplates, which float above the surface of the board (see Example 2),results in dampening of the rider's movements with respect to the boardand loss of control, an undesirable sensation. I have found that theparadox arises because, although freedom of movement of the ankle in theboot binding is essential to good riding, there must also be torsionalstiffness—the rider's motions must be resisted by an optimal level ofstiffness in the binding so that the legs cannot simply angle back andforth, but rather the binding resists this torsional motion (in theengineering sense) with a spring-like stiffness, allowing the rider toapply pressure at the desired segment along the length of the board.

The board is controlled by the bite of its edges in the snow. The ridersteers by relocating pressure from one side of the board to the other aswell as from nose to tail. Toeside and heelside turns on a snowboardinvolve a complex combination of dorsiflexion and plantar flexion, plusthe roll of the calcaneus, talus, and subtalar joint, nosewise andtailwise on the board. While these motions would seem to be favored by acompletely loose binding, in fact, an optimal torsional bindingstiffness is required. Torsional stiffness is the spring force in thebindings that opposes the rider's motion. For every force, there is aforce in the opposite direction. This opposing force translates therider's motion into pressure on the desired section of the board. Whenthe rider bends downslope, for example, the boot bindings transmitpressure onto the nose of the board. When the rider bends upslope, theboot bindings transmit pressure onto the tail of the board. Similarforces come into play as the rider leans toeside or heelside. If thebindings lack torsional stiffness, the ability to apply control pressureto the intended segment of the board is decreased. If the bindings aretoo stiff, the legs cannot pivot, and the rider loses balance andcontrol. Therefore, there is an optimal stiffness, providing an optimalmix of freedom of motion and board control.

While hard ski boot bindings are too stiff to allow the range of motionmost snowboarders prefer, the splitboard systems of the prior artincorporate a soft boot binding with an adaptor mounting plate that isnot stiff enough. The rider can readily bend at the ankle, but cannotprecisely transmit that force as a directed pressure at the desiredsegment of the board.

A problem addressed by this invention is thus one of enhancing thetorsional stiffness of snowboard boot bindings for use with splitboardsin “snowboard riding mode”, and simultaneously improving performance andcomfort of the equipment in free-heel “ski touring mode”. There is anunmet need for dedicated splitboard soft boot bindings with stiffness,weight, and heel height designed for today's splitboard riding styles.

SUMMARY OF THE INVENTION

The most relevant teachings of the prior art focus on a boot bindingwith one or more adaptor mounting plates—so that boots and boot bindingsdesigned for snowboarding can be adapted for use with splitboards. Thisapproach is problematic, adding weight, instability, and decreasing thetorsional stiffness (or spring constant) of the boot bindings. Nosolution has been offered in the prior art that eliminates the weightand height of the essentially ubiquitous “adaptor mounting plate” and,as recognized here, supplies the right amount of stiffness in the bootbinding on the ankle to optimize rider control, while remainingcomfortable and responsive for the soft boot rider.

Any solution must also allow the rider to easily reposition the bootswhen switching from snowboard riding to ski touring configuration, andthe performance in ski touring configuration must also be improved.

I teach here that the prior art adaptor mounting plate, which serves thefunction of adapting both snowboard-type soft-boot bindings and hardboot bindings to the snowboard mounting blocks and also to the skitouring mounting brackets of the prior art, can be advantageouslyeliminated. The adaptor mounting plate, which is an essential componentdisclosed in single-embodiment patents such as U.S. Pat. No. 5,984,324and U.S. Pat. No. 6,523,851, can be replaced with a box girder, in whichthe box girder is integral to the boot binding lower. I have obtainedstiffer torsional spring constants in the boot bindings through thismethod of construction. While not being bound by theory, this teachingis a new solution to the problem of boot binding structural mechanics,and is shown to have unexpected advantages that improve the snowboardride.

Disclosed here are improved boot bindings optimized for splitboarding.By eliminating the adaptor mounting plate, and subsuming its functionsas part of an integral boot binding lower, multiple improvements in formand function are achieved. Unneeded weight is eliminated (about 12 oz,or almost 400 gm) per pair of bindings. Reduction in heel heightrelative to the board surface results in a lower center of gravity onthe board, for better balance and control. Removal of the adaptormounting plate also increases the firmness of the foot and ankle contactwith the board surface, and eliminates the looseness, flex, or “play”between the multiple mechanical components of the prior art that dampenthe board's responsiveness to the rider's movements.

Surprisingly, free heel ski performance is also improved. For one, byreplacing the pivot pin used with the prior art adaptor mounting platewith a longer pivot pin mounted through the structural girder at the toeof the integral boot binding lower, wear on the parts is dramaticallyreduced. In the preferred embodiment of Example 1, the pivot pin islubricated and reinforced by ultrahigh molecular weight polyethylene(UHMWPE) used as the spacer material in the toe of the integral bootbinding lower. This eliminates oval mounting-hole deformationcharacteristic of prior art pivot pin mounting cradles. Also, broaderand more firm toe contact with the board is obtained, improvingperformance in telemark skiing. Snow, which invariably can pack up underthe boots and mounting blocks during skiing and snowboarding, is ventedout under the heel, easing the switch from ski touring to snowboardriding configuration, and vice versa.

As demonstrated here, control of the board is improved by eliminatingcumulative elastic and inelastic deformation that is readily observablein boot adaptor fittings of the prior art (see Example 2), deformabilitythat is attributable to the adaptor mounting plate, its associatedhardware, and to flex in cantilevered elements of the base plate.Comparative field studies performed with embodiments of this inventionshow that the deformability problem clearly improved: the base of theboot is securely and broadly mounted to the board, and the torsionalspring stiffness is increased, while maintaining the desired freedom ofmovement.

Thus these inventive improvements solve unmet needs in optimizing bootbindings for splitboarding: by eliminating the irksome adaptor mountingplate and 4-hole disk, by grippingly securing the rider's boots low onthe board for a stable and comfortable ride, and by use of a boxgirder-type construction, in combination with a boot binding upper, thatsupplies the required torsional stiffness to the ankle.

The improved embodiments will now be described in more detail in thedrawings and remaining disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings provide information concerning selected current-bestembodiments of the invention and are therefore not to be consideredlimiting of the scope of the claims.

FIG. 1 is a perspective view of a sandwich box girder-type of bootbinding lower with heel cup, the construction of which is described inExample 1.

FIG. 2 is a perspective view of an inventive boot binding lower withheel cup. The double arrow indicates direction of movement as the bootbinding lower slides onto the snowboard boot mounting assembly for usein snowboard riding configuration.

FIG. 3 is an exploded view of a sandwich box girder-type of boot bindinglower, with frontal perspective.

FIG. 4A is an exploded view of a sandwich box girder-type of bootbinding of Example 1, with heel perspective. For comparison, FIG. 4Bshows a boot binding of the prior art (per U.S. Pat. No. 5,984,324).

FIG. 5A is an elevation view of the heel of an inventive boot bindinglower, with heel cup, of Example 1 in snowboard riding configuration.For comparison, FIG. 5B presents the same view of the heel of a bootbinding of the prior art (per U.S. Pat. No. 5,984,324).

FIG. 6 is a plan view drawn from the underside of an inventive bootbinding.

FIG. 7 is a longitudinal section, with elevation, taken as noted on FIG.6.

FIG. 8 is a sketch of a pair of integrated boot binding lowers, withheel cup, straddling a splitboard in snowboard riding configuration. Thetoe pivot and climbing bar hardware used with the boot binding lowers inski touring configuration are also shown.

FIG. 9 is an elevation view of the free heel “telemark” pivot action ofa boot binding lower of Example 1 attached to a toe pivot pin assembly.

FIG. 10 is an exploded view showing a toe pivot mechanism.

FIG. 11 shows a longitudinal section of an integrated boot binding lowermounted in ski touring mode. Shown are mechanical details of a toe pivotand climbing bar assemblies with the climbing bar down. The location ofthe transverse section of FIG. 12 is also shown.

FIG. 12 shows a transverse section through the heel of a boot bindinglower mounted in ski touring mode with the climbing bar down.

FIG. 13 shows a longitudinal section of an integrated boot binding lowermounted in ski touring mode. Shown are mechanical details of a toe pivotand climbing bar assemblies with the climbing bar up. The location ofthe transverse section of FIG. 14 is also shown.

FIG. 14 shows a transverse section through the heel of a boot bindinglower mounted with the climbing bar up for ski touring mode.

FIG. 15 shows a longitudinal section of a boot binding of the prior artmounted in ski touring mode. Shown are mechanical details of the toepivot and climbing bar assemblies with the climbing bar down. Thelocation of the transverse section of FIG. 16 is also shown (per U.S.Pat. No. 5,984,324).

FIG. 16 shows a transverse section through the heel of a boot bindingbase plate of the prior art mounted in ski touring mode with theclimbing bar down.

FIG. 17 shows a longitudinal section of a boot binding of the prior artmounted in ski touring mode. Shown are mechanical details of the toepivot and climbing bar assemblies with the climbing bar up. The locationof the transverse section of FIG. 18 is also shown (per U.S. Pat. No.5,984,324).

FIG. 18 shows a transverse section through the heel of a boot bindingbase plate of the prior art mounted with the climbing bar up for skitouring mode.

FIG. 19 is an assembly view of the typical elements of a boot bindingupper on the integral boot binding lower of FIG. 3.

FIG. 20 is an alternate embodiment for a pivoting means of the toe pivotblock assembly.

FIG. 21 is an alternate embodiment for a pivoting means of the toe pivotblock assembly.

DETAILED DESCRIPTION OF THE INVENTION

1. Definitions

Certain meanings are defined here as intended by the inventor, ie. theyare intrinsic meanings. Other words and phrases used here take theirmeaning as consistent with usage as would be apparent to one skilled inthe relevant arts. When cited works are incorporated by reference, anymeaning or definition of a word in the reference that conflicts with orobscures the meaning as used here shall be considered idiosyncratic tosaid reference and not relevant to the meaning of the word as used inthe present disclosure.

Board—a low-friction extended, generally planar surface intended forsupporting a standing person while sliding over snow or ice, andselected from the group snowboard and splitboard.

Splitboard—a combination consisting of two separable ski members thatcan be joined at opposing lateral edges to form a snowboard. The skimembers are typically shaped so as to approximate the right and lefthalves of a snowboard respectively. The tips of the ski members aregenerally secured together in the snowboard configuration by use ofhooks and pins, or the like, but the relative stiffness of the couplingis largely the result of the mechanics of the transverse union formed bythe boot bindings straddling the separate ski members.

Boots—are of three general types, i.e., hard boots, soft boots andhybrid boots (for example “plastic mountain boots”) which combinevarious attributes of both hard and soft boots. Hard boots areexemplified by alpine and telemark ski boots and typically employ amoderately stiff or very stiff molded plastic shell for encasing arider's foot and lower leg with minimal foot movement allowed by theboot. Hard boots conventionally are secured to the board using platebindings that include front and rear bails or clips that engage the toeand heel portions of the boot.

Soft boots, as the name suggests, typically are comprised of softermaterials that are more flexible than the plastic shell of a hard boot.Soft boots are generally more comfortable and easier to walk in thanhard boots, and are generally favored by riders that engage inrecreational, “freestyle” or trick-oriented snowboarding, or alpineriding involving both carving and jumping. Soft boots are conventionallysecured to the board with either a strap binding, a step-in binding withlateral clamp (such as US 20020089150), or with the flow-in bindings,clickers, or cinches of hybrid bindings known in the art (such as U.S.Pat. No. 5,918,897 to Hansen and 6173510 to Zanco).

Ski tour or touring—When used as a noun, indicates: a trip through areastypically away from ski resorts, referred to as the backcountry, whichmay include traversing flat areas, ascending inclined slopes anddescending slopes using one or several of the following pieces ofequipment: skis, poles, snowshoes, snowboards, or splitboards. When usedas a verb, indicates: to enter the backcountry, typically away from aski resort, and perform one or more of the following: traverse flatareas, ascend inclined slopes, and descend slopes using one or more ofthe following pieces of equipment: skis, poles, snowshoes, snowboards,or splitboards.

“Ride” or riding—a noun or verb used by snowboarders to indicate thedistinctive downhill riding experienced by a rider on a snowboard (or ona splitboard in snowboard mode). Snowboarders ride, skiers ski.

Ski touring configuration or mode—indicates a configuration in which thetwo ski members are separate and are attached one to a leg, typicallywith a free heel binding to facilitate traversing terrain and ascendingslopes. When used to describe a splitboard configuration, indicates thatthe ski halves have been separated and the rider is ski touring on theseparate ski members attached to each foot.

Ski mounting assembly—refers to hardware, brackets or blocks secured onthe surface of each ski, generally centrally placed, so that bootbindings can be fastened to them, one boot to a ski, in the ski touringmode or position. In the most common device, a ski touring pin cradle isused with a pivot pin or pins with the pivot axis extending through thetoe of the boot binding, the purpose of which is to provide a hingedcoupling between the boot and its counterpart ski member, as in telemarkskiing and “free heel” skiing. A ski mounting block may take the placeof the pin cradle and may be used with boot mounting tongues, cables, orother pivoting means. Bushings may be used to extend the life of thewearing surfaces. Incorporated herein by reference with respect topivoting means are U.S. Pat. No. 5,649,722 to Champlin, U.S. Pat. No.6,685,213 to Hauglin, US 20050115116 to Pedersen, U.S. Pat. No.5,741,023 to Schiele, and their references cited.

Herein, where a means for a function is described, it should beunderstood that the scope of the invention is not limited to the mode ormodes illustrated in the drawings alone, but also encompasses othermeans commonly known in the art at the time of filing and other meansfor performing the equivalent function that are noted or cited in thisspecification.

Snowboard riding configuration or mode—indicates a configuration inwhich the right and left ski members are joined at opposing lateraledges to form a snowboard and the rider mounts the board with both feetspaced and secured in the snowboard mounting block assemblies.

Snowboard mounting block assembly—refers to prior art flanged mountingblock elements secured to the ski members of a splitboard so that theycan be conjoiningly and flangedly interlocked in the snowboardconfiguration by extending the boot bindings across them. For example,the snowboard mounting block assemblies of FIG. 2 and FIG. 6, asillustrated here, are derived from the prior art (See U.S. Pat. No.5,984,324). In practice, paired snowboard mounting blocks areproximately positioned on the opposing ski members to, forming a “slidertrack” to receive a boot binding traversing the two ski members. Thesnowboard mounting block assembly elements are thus positioned to extendthe boot bindings from one ski member to the other conjoining the skimembers in the form of a snowboard.

Integral boot binding lower—refers to a sandwich box girder forming thebase plate and the lower aspect of a boot binding (or of each of a pairof boot bindings), and having a top plate, bottom plate, medial web,lateral web, and ends modified for the heel and toe, where the web ismade of a structural spacer material or “core”, laminated, molded,glued, solvent-welded, or affixed between the top and bottom plates, andthe bottom plate is formed as a flanged box-ended channel capable ofreceiving and flangedly interlocking or conjoining the two snowboardmounting block assemblies, one front of center (anteriorly placed) andone back of center (posteriorly placed) on the conjoined ski members inthe snowboard riding mode. The integral boot binding lower may includeformed elements such as side rails for securing the boot, a heel cup, aheel brace or highback, brackets for attaching straps, a toe riser, orother elements formed from the materials that make up the integral bootbinding lower. In the snowboard riding mode, the boot heels aregenerally secured to the board. Provision is also made in the integralboot binding lower for the “free heel” ski touring mode by providing apivoting means at the toe for attaching the boot binding to the skimounting assembly. Integral boot binding lowers may be fabricated fromsheet metal plates, such as aluminum or aluminum alloys, or fromreinforced plastic plates, either molded or extruded. Ultrahighmolecular weight polyethylene is a preferred material for the spacermaterial forming the webs because of its toughness, resistance to wear,and lightness, but other thermoplastics such as nylon, polypropylene,Teflon, and polyamides or reinforced composites such as polyester fiber,carbon fiber, polyamide fiber, filled nylon, or aramid fiber thermosetsmay also be suitable.

Upper boot binding, or boot binding upper—refers to elements of a bootbinding attached to an integral boot binding lower with fasteners ormolded in place, and generally includes shaped supports that contact andsecure the boot, for example a highback which may be foldable, a heelcup, rails, and one or more straps, most commonly a heel strap and a toestrap. The upper may also include a toe riser, shell, cushioning, andcomponents that are engaged when the boot is inserted. These elementsare generally formed of assemblies separable and distinct from theintegral boot binding lower, for example various aluminum, titanium, andsteel alloys (used in hardware, ratchets, heelcups, cables, baseplates,highbacks, etc), neoprene rubber, silicon rubber, low densitypolyethylene, polypropylene, fiberglass, nylon, filled nylon, leather,fabrics, stitching, EVA foam padded cores, and the like. The upperelements provide stiffness to the boot binding when attached to a rigidintegral boot binding lower and thus contribute to the torsionalstiffness of the boot binding as a whole. Selected upper elements aretypically adjustable, such as the heel cup, allowing fitting for bootsize and personal adjustment within the underlying limits of the design.

Receiving and grippedly conjoining—refers here to the action ofslidingly and reversibly engaging a snowboard mounting block assembly or“slider track” with the adaptor mounting plate of the prior art or by abox girder with box-ended channel and internal flanges so as to conjointwo ski members in snowboard riding configuration. In the inventivedevice of Example 1, the box-ended channel formed in the base plate ofthe integral boot binding lower flangedly interlocks with flangedsurfaces of the snowboard mounting block assembly. In a preferredembodiment, the box end of the box-ended channel prevents the integralboot binding lower from slipping over the snowboard mounting blockelements from the heel. A transverse pin or other locking means may beused to secure the boot bindings at the open end of the box-endedchannel at the toe. When this locking means is opened, the boot bindingsmay be slidingly removed from the snowboard mounting block assembly.

Adaptor mounting plate—refers to an intermediate mechanical device ofthe prior art for securing a 3- or 4-hole disk-mounted boot binding tothe snowboard mounting blocks and ski touring tabs on a ski, snowboard,or splitboard. In its preferred configuration, the adaptor mountingplate, or “slider plate”, consists of a C-channel constructed of heavyextruded aluminum alloy plate. Clamshell adaptor plates have also beenused.

4-hole disk—a component of a standard board binding of the prior artthat mechanically couples the body of the binding base plate to theboard. This disc is circular and can be rotatingly coupled to thebinding, thus allowing the rider to select an angle of placement foreach foot with respect the longitudinal axis of the board. Three-holedisks have also been used.

Torsional stiffness—in its simplest engineering analysis, torsionalstiffness can be approximated by a form of Hooke's law relating torqueto deformation:T=K*Δθwhere T is torque, K is a spring constant, and Δθ (theta) is the angulardeformation or displacement relative to the heel pivot. A more complexmodel including elastic shear modulus, loss shear modulus, and dampeningcoefficients may also be formulated.

Foot roll—is a term used in the art to denote the freedom of angular legmovement experienced by a board rider. The rider uses foot roll to shiftthe pressure or “bite” of the board on the underlying snow. Foot roll isessentially the “Δθ” in the equation for torsional stiffness.

Highback—An element that extends from the heel up the calf in part, andserves as an ankle brace to control the heel and leaning on turns, andcan be rigid, semirigid, or flexible. The highback can also used tosecure the boot into the boot binding upper in some step-in bootbindings. Highbacks typically have a pivot that allows them to be laidflat, decreasing the amount of storage space needed for the bootbindings.

2. Detailed Description

Two groups of drawings will be discussed. In the first section, FIGS.1-8, the engineering of an integral boot binding lower in snowboardriding mode will be described. In the second section, FIGS. 9-18describe the workings of the integral boot binding lower in ski touringmode. FIG. 19 illustrates assembly of some of the common features of anupper boot binding typical of marketable products of the presentinvention.

Referring now to FIG. 1, this perspective view shows an integral bootbinding lower (1) with sandwich box girder (2) construction based on thecurrent working prototype of Example 1. The box girder consists of threematerial layers: a top plate (3), a bottom plate (5), and a centerspacer or core (4) that serves as the side webs of the girder. The boxgirder may be tapered or untapered.

The top plate and bottom plate shown in this illustration are made ofsheet metal as described in Example 1, but may also be made ofreinforced plastic composites, either as molded or extruded sheets. Asshown in this embodiment, folded tabs of the top plate form side rails(6). An optional heel cup (7) may be fastened to the top plate rails.Provision for attachment of a toe strap (11), heel strap (12), andhighback (13) are also illustrated. A single hole may be used for boththe highback and heel strap.

The spacer or core web material of the girder is preferably alightweight material, but carries both compression, tensile, and bearingloads. The material, such as a plastic, is characteristically tough andcan be machined, drilled or molded.

Box-ended channel (9) and bottom plate internal flanges (10) form agripping means that joins the sandwich box girder to mated snowboardmounting blocks inserted in the box-ended channel. Thus FIG. 1demonstrates several structural elements of this embodiment, thesandwich box girder with side webs, the box-ended channel, and also ameans for pivoting the structure at the toe, here indicated by a thetransverse axial hole (14) for insertion of a toe pivot pin as describedin FIG. 9 and FIG. 20. The toe pivot pin serves a dual function, also tolock the box-ended channel in place as will be shown in FIG. 2.

The integral boot binding lower provides rigidity in joining the two skimembers, but also must provide a rigid platform for the boot bindingsthat secure the boot to the board. Without adequate stiffness in theintegral boot binding lower, the torsional stiffness of the upper bootbindings will be correspondingly insufficient.

Note that in the prototype of Example 1, the adaptor mounting plate ofFIG. 4B is absent, and there is an integration of the splitboard joiningdevice (here a sandwich box girder, see FIG. 2 and FIG. 8) with a bootbinding device (or boot binding upper) as in FIG. 19.

The integral boot binding lower is fitted with a boot binding upper. Thepurpose of the boot binding upper is to further secure the boot to thebase plate and to provide freedom of motion with the required level oftorsional stiffness. Upper bindings include heel cup, toe strap, heelstrap, or step-in binding. Optional features such as padded rails, archsupport, toe riser, heel cushion, heel riser, base plate, anti-slipplate, and exterior shell may be provided. A boot binding upper, theform of which can be highly varied and examples of which are well knownin the prior art, is shown for example in FIG. 19. Selected elements ofthe boot binding upper, such as straps or step-in bindings, provideadjustments for fit and aid in establishing torsional stiffness.

The bottom plate shown here is machined to form a box-ended channel (9)with internal flanges (10). The box-ended channel is open under the toeend of the box girder, but does not extend all the way to the heel, soas to capture the snowboard mounting block assembly. This function ofthe box-ended channel is illustrated in FIG. 2. The double arrow showshow the box-ended channel slidingly receives and engages a snowboardmounting block assembly (17) so that the internal flanges of theintegral boot binding lower grippingly conjoin the flanges (22) of thesnowboard mounting block elements (18, 19), the elements becomingflangedly interlocked. Note that the flanges of the two mounting blockelements that make up the snowboard mounting block assembly are paralleland aligned for engaging the internal flanges of the box-ended channel.

When the boot binding flanges (10) extend under both snowboard mountingblocks (18, 19), the two ski members (15, 16) are rigidly conjoined. Atoe locking pin (23) inserted at (14) prevents the assembly fromslipping and is held in place with snaps (24). Thus in snowboard ridingconfiguration, the sandwich box girder (1) traverses or “straddles” thepair of skis, and flangedly interlocks them in the form of a snowboard,also fixing the boot heel in place. Optional heel cup 7 is shown herefor clarity. The rigidity of the underlying girder, its contact with theboard surface and low profile, ensures a solid platform for the rider'sboots and the boot binding upper.

A pair of internal pucks (20, 21) are supplied with fasteners forsecuring the pair of snowboard mounting blocks (18, 19) to the pair ofski members (15, 16), and permit adjustment and alignment for individualfit. The snowboard mounting block assembly (17) is adjusted to thepreferred stance or angular orientation of the user and, in oneembodiment, may be set up for the position of the user's feet in eithera left-foot-forward or a right-foot-forward mode.

FIG. 3 is a construction detail of the integral boot binding assembly ofExample 1. Three mechanical elements, the top plate (3), spacer webs (4,27) and bottom plate (5), are clearly shown as forming a sandwich boxgirder. In this view, the box-ended channel (9, directional arrow) isshown under the toe riser (25) and between the lateral and medial web(4, 27). Correspondingly, a snow vent (29, directional arrow) is formedunder the heel riser (26) between the medial and lateral spacers (4,27). The web elements are fitted or molded to the top and bottom plates,and the truss-like character of the box girder is strengthened bymultiple fasteners (30) extending through the sandwich. Adhesives,lamination, or solvent welding may also be used to form the sandwich boxgirder, eliminating the need for fasteners.

Also adding to the truss character are the upward-folding side rails ofthe top plate (6). The top plate may also be used to make provision forattachment of elements of the boot binding upper with fasteners.Provision for a toe strap is provided at 11, and for a heel cup at 28 onthe optional top plate side tabs (6).

FIGS. 4 and 5 provide comparative views of the embodiment of Example 1with a boot binding of the prior art.

FIG. 4A again shows the basic construction of the integral boot bindinglower of Example 1, but from a heel view. Shown are the three elementsof the sandwich box girder: top plate (3), middle spacers (4, 27), andbottom plate (5), with fasteners (30).

For comparison, a prior art design is shown in the accompanying panel,FIG. 4B. In this side-by-side exploded view, the differences are readilyseen between the inventive sandwich box girder of Example 1 and theprior art design of U.S. Pat. No. 5,984,324.

An essential element of the most popular prior art design is the adaptormounting plate (40), which is an anodized C-channel formed from extrudedaluminum alloy. This adaptor mounting plate has flanges (42) thatgrippingly conjoin the snowboard mounting block assembly (as shown inelevation in FIG. 5B). The prior art assembly also dictates a 4-holedisk (31) used as a universal mount for the sort of soft boot bindingupper base plate illustrated here by 32. Provision is made here for bootstraps (38, 37) and for a heel cup (36) on side rails 35. The bootbinding upper is fitted individually per foot, shown here with a lefttoe riser (33) and a heel riser (34). By industry standard, the 4-holedisk fasteners (44 s, 44 w) are at 4 cm corners. Tee nuts (44 n) areused to secure the boot binding to the adaptor mounting plate. A gasket(39) is used to fit the boot binding upper (32) to the adaptor mountingplate (40). Note the heel stop tab (43) and the toe pivot axis (41), twoareas where the adaptor mounting plate is very prone to metal fatigue.

In the prototype of Example 1 (compare FIG. 4A with FIG. 4B), theadaptor mounting plate has been eliminated. An integrated boot bindinglower, the sandwich box girder, takes its place. The box girder servesin snowboard configuration both as a means to conjoin the two skimembers and as a means to provide a rigid platform for supporting theelements of the boot binding upper. However, the design has otheradvantages as well, as become apparent by comparison.

FIG. 5B is an elevation view of the heel of the prior art boot bindingwith adaptor mounting plate (40) mounted in snowboard ridingconfiguration. The flanges of the C-channel can be seen gripping matedflanges (22) on the filled nylon snowboard mounting block element (18).Also visible is a puck assembly (20), although the inner assemblies areobscured by the heel stop tab (43).

The base of the soft boot binding upper (32), side rail (35) and anoptional heel cup (46) can also be seen in this view. The heel riser(34) partially obscures the toe riser (33), which is higher for the leftbig toe. Boot bindings optionally may be designed to accept only a leftor right foot, or may be interchangeable.

Note the height of the base plate above the upper board surface (15) andcompare with FIG. 5A, which is an elevation view of the heel of theembodiment of Example 1. The play of mechanical elements 18, 20, 22, 42,40, 29 and 32 of FIG. 5B is eliminated in the design of FIG. 5A. In FIG.5A, elements 18, 20, and 22 connect directly with the boot binding lowerelements 5 and 10, and the rest of the structure is rigidly formedaround those impinging flanges. Allowing for normal clearances, thebottom plate of the box girder is in contact with the upper surface ofthe board.

FIG. 5A again also shows the presently preferred sandwich construction(2) of bottom plate (5), web (4) and top plate (3). Side rails (6) andheel cup (7) provide added strength.

Visible under the heel riser (26) is an open space above puck (20) andbounded on the left and right by the webs (4, 27). This gap is the snowvent (29), which keeps the mechanism free of impacted snow.

FIG. 6 views the construction of the box girder from the underside. Thebottom plate (5) is observed to overlap flanges (33) on the snowboardmounting block elements (18, 19) of the snowboard mounting blockassembly (17). The pucks (20, 21) engage the surface of the board whichattaches to this underside (hardware not shown).

The side rail (6) of the top plate (3) is also visible, as is the bandof metal forming the heel cup (7). The cutout in the profile of thebottom plate at the inside heel edge of the box-ended channel isdesigned for the heel rest of a commercially available ski mountingassembly design, as will be described in FIGS. 12 and 14. The snowboardmounting blocks are chocked against the heel crossbeam of the bottomplate, and are locked from forward motion by the toe pivot and lockingpin 23.

Also shown in FIG. 6 is the plane of a longitudinal section taken forFIG. 7. FIG. 7 includes parts of the elevation view for clarity. Insection, the box girder (1), manifested in the presently preferredembodiment as a sandwich box girder (2), is seen extend across two skimembers (15, 16) and is held in place on the snowboard mounting blockassembly (17). Two snowboard mounting blocks (18 and 19), one on eachski, are locked between the heel of the box girder and toe pivot andlocking pin (23) underneath the toe riser (25).

The adjustment of the pucks to position and align the snowboard mountingblock elements is provided for by screws in slots 48 and 49 of thesectional view (not shown: the screws mate with threaded insertsembedded in the ski members).

FIG. 8 shows a fully assembled splitboard of the invention, withintegral boot binding lowers in the snowboard riding configuration. Twoski members (15, 16) are joined at a pair of snowboard mounting blockassemblies by conjoining integral boot binding lowers with sandwich boxgirder construction. Heel cups (7) are shown for clarity.

Also shown are the hardware assemblies used in ski touring mode, whichare more centrally placed on the ski members. Item 51 is a ski toe pivotassembly; item 52 a ski heel rest and climbing bar assembly. These twoassemblies form the ski mounting assembly (50), which is used in skitouring configuration, as will be discussed next.

The user may readily remove the boot bindings from the snowboard bootmounting block assemblies and reattach them to the ski mountingassembly. The binding assemblies of the present invention permit rapidtool-free conversion from the ski mode to the snowboard mode, or viceversa.

FIG. 9 is an elevation/action view showing an integral boot bindinglower of Example 1 at rest on a ski (15) in the ski mounting assemblyintroduced in FIG. 8. The toe of the sandwich box girder (2) is securedwith a pin (23) through the webbing under the toe riser (25), whichengages a toe pivot mounting cradle and block (53, 54) of the ski toepivot assembly (51). Under the heel (26), a heel rest and climbing barassembly (52) support the boot binding off the surface of the ski. Theclimbing bar assembly consists of a climbing bar (55), which is hinged,and a heel rest pad (56).

The functional mechanism is revealed in more detail in the lower panel.The skier can alternate from heel stance (as shown in the top panel) totelemark stance (as shown in the lower panel). In telemark stance,partial weight is resting on the toe pivot cradle and pin. The life andperformance of this hardware is dramatically improved in the prototypeof Example 1, through use of a longer pivot pin (23), the webs of UHMWPEto lubricate the pin, and a wider mounting area to distribute theweight.

In FIG. 10, an exploded view is used to better show the improvements inthe toe pivot assembly (51). The two webs of the box girder (4, 27)pivot at 14 on pivot pin (23), which is clasped in place with cotterpins (24) or similar fasteners. The fulcrum of the pivot runs throughtoe pivot pin cradle (53), which is supported by a plastic molded block(54). The elements of the fulcrum are affixed to the ski (15) with 3mounting fasteners (57).

In FIG. 1, the elements of the ski mounting assembly are shown inlongitudinal section. The location of the transverse section for FIG. 12is also shown. The longitudinal slice cuts the ski (15) toe assembly(51) and heel assembly (52). The pivot pin or axle (23) is located inthe web below toe riser (25), and is sandwiched between the bottom andtop plates (3, 5).

At the heel (26), climbing pin assembly 52 consists of a heel rest pad(56) and climbing bar (55). In FIG. 12, the corresponding transversesection through the heel, contact is seen between the heel rest pad andthe bottom surface of the top plate (3). The heel rest lies entirelywithin the box-ended channel (9) of the full assembly. An indication ofthe hinged nature of the climbing bar is suggested.

In FIGS. 13 and 14, the action of the climbing bar (55) is betterillustrated. The hinge or pivot point of the climbing bar is formed bybending paired “ells” in the steel bar (55 p) and clipping them into thebase block of the climbing bar assembly, which also serves as the heelrest (56). Heel rest pad 56 squarely contacts the underside of the topplate (3 u). The underside of the bottom plate (5 u) extends forward andbehind the climbing bar assembly without interference. Medial andlateral webs (4, 27) and toe pivot pin (23) are also shown in thiscutaway view.

FIGS. 15 through 18 compare the ski mounting assembly of the prior art.Some elements are used in common. These include the toe pivot assembly(51) and the climbing bar assembly (52), but differences can be noted,for example by comparison of FIG. 16 with FIG. 14. Note the widersupport base in FIG. 14 (Example 1) as compared to the prior art (FIG.16). Pivot pin 58 is clearly shorter than pivot pin 23. Also note therest point of the heel stop tab (43) of the prior art (a folded tab ofmetal) on a facet of the climbing bar housing (52). No other contactpoint is provided. Interestingly, the metal tab is prone to softenadjacent to the fold where it is work hardened and has been observed tobreak off with continued use.

FIG. 18 is also instructive. When compared to FIG. 14, it is clear thatthe prior art boot binding, at toe stance on the climbing bar, is muchhigher off the board than in the mechanism of Example 1. The narrownessof the toe pivot fulcrum (51, 58) is also apparent.

FIG. 19 demonstrates how the completed boot binding of Example 1 wasfabricated. The integral boot binding lower (1) is shown fullyassembled, as in FIG. 3. Under it, inside box-ended channel 9, the twoski members (15, 16) are conjoined by its grip on the snowboard mountingblock elements as shown in FIG. 2. The completed assembly is then lockedin place with toe pivot and locking pin (23) running through the toeriser (25).

In this example, the elements of a boot binding upper consist of: heelcup (7), toe strap (60), heel strap (61), and highback (62). Fastener 12secures the heel strap and high back to the heel cup in any of the threeplacement holes shown. Fasteners (8) secure the heel cup to the siderails (6) of top plate (3). Fasteners (11) secure the toe strap to theside rails.

FIG. 20 illustrates an alternative embodiment of the toe pivot assembly(51) shown in FIG. 9. Here, a polyethylene block (63) is milled toperform the function of toe pivot pin fulcrum. Compare this figure withFIG. 10. Equivalent pivoting means are readily gleaned from the priorart.

FIG. 21 illustrates an alternate embodiment of the toe pivot assembly(51) shown in FIG. 9. Here, a toe pivot pin cradle (64) contains captivebushing (65), held in place by retaining rings (66), to reduce orprevent degenerative wear of the critical toe pivot bearing surfaces.

In one embodiment, the invention is an improvement of a splitboard bootbinding assembly, comprising an integral boot binding lower, saidintegral boot binding lower further comprising a sandwich box girderhaving a top plate, a bottom plate, a medial web, a lateral web, a heelend and a toe end, wherein said bottom plate comprises a box-endedchannel and inside flanges for receiving and grippingly conjoining saidboot binding system to a snowboard mounting block assembly affixed to asplitboard.

In other embodiments, the boot binding combination of the inventionincludes an integral boot binding lower for grippingly conjoining theboot binding assemblies to snowboard mounting blocks on a splitboard,and a boot binding upper—but eliminates the adaptor mounting plates ofprior art designs.

In a preferred embodiment, the boot binding of the invention comprises acombination of no adaptor mounting plate, an integral boot binding lowerfor grippingly conjoining said boot binding system to a snowboardmounting block assembly affixed to a splitboard, and a boot bindingupper, the whole combination of which provides an improved level oftorsional stiffness for splitboard riders. The elimination of theadaptor mounting plate is made possible by the integration of asplitboard joining device, here the integral boot binding lower, withthe upper boot bindings. Elimination of the adaptor mounting plate trimsexcess elastic and inelastic deformation from the boot binding system,and the combination of an integral boot binding lower with suitable bootbinding uppers provides an increased level of torsional stiffness notpreviously available for splitboard riders.

My recognition of torsional stiffness as a performance issue forsplitboard boot bindings frames the problem, and I also provideinventive solutions here. While the prototype of Example 1 has beendescribed in detail, other designs and materials of fabrication canprovide an improved level of torsional stiffness for today's splitboardriders.

Although the invention has been described in connection with certainillustrative embodiments, it should be apparent that many modificationsof the present invention may be made without departing from the scope ofthe invention as set forth in the claims.

EXAMPLES Example 1

A Drake F-60 snowboard binding with integral heel cup and highback wasmodified in a shop by removing the base plate and 4-hole disk andsubstituting in their place a sheet of 2.5 mm aluminum with side railsfolded up to form a shallow channel for the boot.

A three dimensional CAD design was sent to a local sheetmetal house thatused a CNC (computer numerically controlled) laser cutter to cut theoutline and holes for the aluminum parts necessary for the bindings.Sheetmetal press brakes were then used to bend the channels of thebindings. Similarly, a CNC milling machine cut out the UHMW polyethylenespacers from a sheet of 16 mm thick plastic. This machine provided allholes, the outline, and contoured surfaces.

Using mounting bolts, the heel and toe straps and highback were securedin place. A total of 10 screws, countersunk, were placed at thecircumference of the base along each side of the sandwich to secure theplastic spacer materials (webs) in position between the aluminum plates.

A milled hole accommodates a longer pivot pin than used in the priorart, and a second smaller hole was placed in the aluminum side rails tosecure a braided cable loop to protect against loss of the snapfasteners. Note that the inner dimensions of the channel formed by theplastic spacers is wide enough to snugly fit over the ski mounting tabsand that the transverse pivot axis lines up with the hole in the skimounting bracket. UHMWPE lubricates the pin and spares wear on the pivotpin cradle mount.

Right and left boot bindings were made in this manner. To assemble thesnowboard, the boot bindings are securely slid over the snowboardmounting blocks and locked in place with a transverse pin and snapfasteners. To switch to ski mode, the boot bindings are slipped off thesnowboard mounting block assemblies and positioned at the toe over theski mounting brackets so that the pivot pin can be aligned through thepivot holes and secured in place with snap fasteners.

Example 2

Mechanical comparisions were made using a splitboard and boot bindingassembly of the prior art versus that of Example 1. A Voile“Splitdecision 166” splitboard was used for the comparisons, and for theprior art testing, Drake F-60 snowboard bindings were mounted asrecommended by the manufacturer on the Voile mounting hardware. The bootbindings were assembled in snowboard riding configuration for thesecomparisons.

Physical measurements of the two boot bindings were also made and arerecorded in Table 1. TABLE 1 Prior Art Example 1 Distance from plane ofboard to bottom of 26 mm 14 mm boot Width in contact with board underlateral 80 mm 120 mm load Weight per boot binding 1182 g 1015 g

To measure deformation under lateral strain, which is related to springconstant K of the boot bindings, the snowboard was clamped to a verticalsurface so that the highback of the boot bindings were mounted parallelto the floor. An 11.3 kg weight was then clipped onto the top of thehighback, and the angle of shear for the two assemblies was compared.Deformation under modest lateral loading was approximately 36% greaterwith the prior art boot binding, indicating an unacceptably lowtorsional stiffness.

The binding system of the new invention was noted to substantiallyincrease lateral stiffness of the boot and to lower the center ofgravity on the boot. In snowboarding tests undertaken under winterconditions on mountainous terrain, the increased lateral rigidity of theinventive bindings was found to result in immediately noticeableincreases in control and responsiveness of the board in downhill ridemode.

Improvements were also noted in telemark ski touring, which wereattributed to the improved toe contact made by the boot with the board,particularly for kick turning.

Weight is reduced by 6 ounces (170 g) on each foot, a 15% weightsavings. This weight savings noticeably decreases the effort required toascend a slope because the weight on each foot must be repeatedly liftedand pushed forward. Weight on the feet requires roughly five times theexertion to move as the same weight carried in a backpack. The weightsavings is had by combining structures such as the baseplate and theslider plate, the original slider plate being nearly wide enough to be abinding baseplate. This savings is also had by eliminating unnecessarystructures like the four hole disk (shown in FIGS. 4 and 17, item 31).The disk adds the ability to adjust the stance angle on a conventionalsnowboard and is the principal component that determines the thicknessof the baseplate. However, with a splitboard, the plastic pucks alsoallow rotation of stance during setup, making the adjustability of the4-hole disk redundant. Voile (Salt Lake City, Utah) states that thebinding should always be connected to the slider at zero degrees. Theprototype fuses these structures at zero degrees without the addedweight and thickness of a four hole disk.

Example 3

A block of UHMWPE, 25 mm thick by 100 mm by 75 mm, is trimmed to fitbetween the lateral and medial spacers of an integral boot binding lowerof FIG. 10. The rear height of the block is trimmed and rounded to fiteasily under the toe riser. A thin rectangular pad is formed from thefront of the block to protect the board surface from abrasion by the toeriser and serve as a shim during telemark ski touring. Using the bootbindings toe pivot holes of Example 1 as a drill guide, a transversehole through the block is made. This hole is dimensioned to accept acaptive bushing (see for example FIG. 21) for use with the longer toepivot pins. Board mounting holes are also drilled and countersunk, sothat the new toe mounting assembly can be fitted onto the existinginserts of the board. A second block is shaped for the other board.These components go into a boot binding interface conversion kit, or“split kit”, for use with the integral boot binding lower of theinvention. TABLE 2 Splitboard Boot Binding Interface Conversion KitFusion boot binding (with integral boot binding lower of pair Example 1)Ski 3-Hole Mounting Bracket w/captive bushing 2 ea (shims available in 2mm increments) 20 mm stainless steel screws 6 ea Heel rest with climbingbar 2 ea Pivot pin and easy-snap retainer ring with runaway cable 2 ea30 mm stainless steel screws 8 ea Crampons with fasteners 2 ea Allenwrench 1 eaNote:Conversion kits compatible with Voile “universal slider tracks”(Voile-USA: Salt Lake City, UT). Snowboard mounting block assemblies areoptional and may be customized by the user.

The foregoing written description has disclosed certain embodimentsillustrative of the engineering principles, materials properties, andinventive steps used to solve the problems addressed by the invention.The invention, however, is not limited to the exact construction,materials and operation shown and described herein; but also includessuch variants, as will be apparent after study of these teachings, tothose skilled in the art.

1. A boot binding comprising an integral boot binding lower, saidintegral boot binding lower further comprising a sandwich box girderhaving a top plate, a bottom plate, a medial web, a lateral web, a heelend and a toe end, wherein said bottom plate comprises a box-endedchannel and inside flanges for receiving and grippingly conjoining saidboot binding system to a snowboard mounting block assembly affixed to asplitboard.
 2. The integral boot binding lower of claim 1, wherein saidlateral web and medial webs are formed from a plastic.
 3. The lateraland medial webs of claim 2, wherein the plastic is ultra high molecularweight polyethylene.
 4. The integral boot binding lower of claim 1,wherein said top and bottom plates are formed from a sheet materialselected from a metal or a plastic.
 5. The sheet material of claim 4,wherein the metal is aluminum or aluminum alloy.
 6. The sheet materialof claim 4, wherein the plastic is a fiber-reinforced plastic.
 7. Theintegral boot binding lower of claim 1, wherein said top plate furthercomprises tabs that are folded upward to form members selected from siderail, heel cup, brace, bracket, heel riser, and toe riser.
 8. The bootbinding of claim 1, further comprising a boot binding upper.
 9. The bootbinding of claim 8, wherein said boot binding upper comprises one ormore members selected from heel cup, highback, base plate, brace, archsupport, anti-slip plate, toe riser, heel riser, exterior shell,cushion, heel strap, toe strap and step-in binding.
 10. The integralboot binding lower of claim 1, further comprising a pivoting means forpivotingly attaching said toe end to a ski member.
 11. The pivotingmeans of claim 10, comprising a pivot pin inserted through said medialand lateral webs at said toe end to engage a toe pivot mounting cradle.12. The integral boot binding lower of claim 1 wherein the heel endcomprises a snow vent formed between said medial and lateral webs.
 13. Aboot bindings kit for a splitboard, comprising: a) a first boot binding,comprised of an integral boot binding lower, wherein said integral bootbinding lower further comprises a sandwich box girder, the bottom plateof said sandwich box girder being formed to comprise a box-ended channelwith flanges for receiving and grippingly conjoining said integral bootbinding lower to a first snowboard mounting block assembly; and b) asecond boot binding, comprised of an integral boot binding lower,wherein said integral boot binding lower further comprises a sandwichbox girder, the bottom plate of said sandwich box girder being formed tocomprise a box-ended channel with flanges for receiving and grippinglyconjoining said integral boot binding lower to a second snowboardmounting block assembly.
 14. The kit of claim 13, further comprising afirst and second ski mounting apparatus.
 15. The kit of claim 14,wherein said right and left ski member mounting assemblies furthercomprise a bushing.
 16. The kit of claim 13, further comprising a firstand second snowboard mounting block assembly.
 17. A combination of asplitboard and boot bindings, having a ski touring configuration and asnowboard riding configuration, comprising: a) a right ski member and aleft ski member, having mounting surfaces centrally, anteriorly andposteriorly; b) a right integral boot binding lower, and a left integralboot binding lower; c) a first snowboard mounting block assembly, and asecond snowboard mounting block assembly; d) a right ski member mountingassembly, and a left ski member mounting assembly; and wherein, saidright integral boot binding lower comprises a sandwich box girder havingtop plate, bottom plate, medial web, lateral web, heel end and toe end,and further, wherein the bottom plate of said right integral bootbinding lower further comprises a box-ended channel and inside flangesfor receiving and grippingly conjoining said first snowboard mountingblock assembly in said snowboard riding configuration; and wherein, saidleft integral boot binding lower comprises a sandwich box girder havingtop plate, bottom plate, medial web, lateral web, heel end and toe end,and further, wherein the bottom plate of said left integral boot bindinglower further comprises a box-ended channel and inside flanges forreceiving and grippingly conjoining said second snowboard mounting blockassembly in said snowboard riding configuration; and wherein, said firstsnowboard mounting block assembly comprises a first right snowboardmounting block element, anteriorly placed on said right ski member and afirst left snowboard mounting block element, anteriorly placed on saidleft ski member, said first right and first left snowboard mountingblock elements receiving and grippingly conjoining an integral bootbinding lower, selected from right or left integral boot binding lower,in said snowboard riding configuration; and wherein, said secondsnowboard mounting block assembly comprises a second right snowboardmounting block element, posteriorly placed on said right ski member anda second left snowboard mounting block element, posteriorly placed onsaid left ski member, said second right and second left snowboardmounting block elements receiving and grippingly conjoining an integralboot binding lower, selected from right or left integral boot bindinglower, in said snowboard riding configuration; and wherein, said rightintegral boot binding lower pivotingly attaches to said right ski membermounting assembly at the toe end, and said left integral boot bindinglower pivotingly attaches to said left ski member mounting assembly atthe toe end, in said ski touring configuration.
 18. A splitboardcombination comprising: a) a first ski member having at least onenonlinear longitudinal edge; b) a second ski member having at least onenonlinear longitudinal edge; c) conjoining apparatus for securing saidfirst ski member to said second ski member to form a snowboard havingnonlinear longitudinal edges; d) a ski mounting assembly secured to saidfirst ski member and a ski mounting assembly secured to said second skimember; e) a first snowboard mounting block assembly positioned toextend a first boot binding between said first ski member and saidsecond ski member, said first snowboard binding block assembly having atleast one snowboard mounting block element secured to said first skimember and at least one snowboard mounting block element secured to saidsecond ski member; f) a second snowboard mounting block assemblypositioned to extend a second boot binding between said first ski memberand said second ski member, said second snowboard mounting blockassembly having at least one snowboard mounting block element secured tosaid first ski member and at least one snowboard mounting block elementsecured to said second ski member; g) a first boot binding, comprised ofan integral boot binding lower, wherein said integral boot binding lowerfurther comprises a sandwich box girder, the bottom plate of saidsandwich box girder being formed to comprise a box-ended channel withflanges for receiving and grippingly conjoining said integral bootbinding lower to said first snowboard mounting block assembly; and h) asecond boot binding, comprised of an integral boot binding lower,wherein said integral boot binding lower further comprises a sandwichbox girder, the bottom plate of said sandwich box girder being formed tocomprise a box-ended channel with flanges for receiving and grippinglyconjoining said integral boot binding lower to said second snowboardmounting block assembly.
 19. The boot binding of claim 8, comprising noadaptor mounting plate.
 20. The boot binding of claim 8, wherein saidboot binding upper and said integral boot binding lower are notconnected by an adaptor mounting plate.